Spark-plug



F. A. HOMEWOOD.

SPARK PLUG. APPLICATION FILED MAR.12. 1921.

M W M Patented Nov. 22, 1921..

FRED A. HOMEW'OOD, 0F GLENDO, WYOMING.

SPARK-PLUG.

Specification of Letters Patent.

Patented Nov. 22, 1921.

Application filed March 12, 1921. Serial No. 451,759.

T 0 all whom it may concern:

Be it known that I, FRED A. HOMEWOOD, a citizen ofthe United States, residing at Glendo, in the county of Platte and State of \Vyoming, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification, reference being had to the accompanying drawin s.

his invention relates to certain improvements in spark plugs, and it is primarily an object of the invention to provide a novel and improved device of this general character which is an improvement on the form of spark plug embodied in my prior pending application, Serial No. 355,348, filed January 31, 1920.

Another object of the invention is to provide a spark plug embodying novel and improved means whereby the primary electrode is effectively cooled in a manner to prevent the firing end or point of such electrode becoming unduly heated or hot enough to scale and whereby the gap ing or arcing of the spark is materially faci itated.

It is also an object of the invention to provide a spark plug with novel and improved means whereby a materially large and intense spark is produced and wherein the gapping or arcing is from the primary electrode to the body or shell proper.

An additional object of the invention is to provide a novel and improved spark plug wherein the primary electrode or conductor is hollow and provided with means whereby a down and up draft may behad therethrough.

The invention consists in the details of construction and in the combination and arrangements of the several parts of my improved spark plug whereby certain im- 1 portant advanta es are attained and the device rendered simpler, less expensive and otherwise more convenient and advantageous for use, as will be hereinafter more fully set forth.

The novel features of my invention wil l hereinafter be definitely claimed.

In order that my invention may be the better understood, I will now proceed to describe the same with reference to the accompanying drawings, wherein:

Figure l is a vertical sectional view taken through a spark plug constructed in accordance with an embodiment of my invention;

Fig. 2 is a view in bottom plan of the device as illustrated in Fig. 1; and

Fig. 3 is a sectional view taken substantially on the line 3-3 of Fig. 1.

As disclosed in the accompanying drawings, B denotes the body or shell of a spark plug and which body or shell is of a conventional type. Held in the body or shell B by the nut N is the insulating core C. Disposed through the core 0 at substantially the axial center thereof is the primary electrode or conductor E.

The periphery of the reduced or connecting end portion of the body or shell B is provided with the external threads 1 but said threads terminate a distance inwardly of the lower or outer end of said portion of the body or shell B. The end portion of the body or shell B outwardly of the threads 1 has pressed therefrom or otherwise formed an inwardly directed and relatively large protuberance 2, preferably parti-spherical in form. The protuberance 2 constitutes the secondary electrode and said protuberance coacts with the firing end portion of the primary electrode in a manner to assure a relatively large and intense spark. This construction 1s preferred because the body or shell B through the secondary contact as afforded by the protuberance 2. permits the requisite travel of the electrical energy with a minimum of resistance.

The primary electrode or conductor E is hollow or tubular and has its firing end 3 closed. Extending longitudinally of the bore 4 of the electrode E is a partition 5 extending from a point in close proximity to the closed or firing end 3 of the electrode to the opposite or outer end of such electrode. The partition 5 divides the bore 4 of the electrode E into the chambers or compartments a and b and the lower end portions of said compartments are in communication one with the other at the firing extremity of the electrode through the port 6 which is provided by the space between the inner end of the partition 5 and the closed 3 of the electrode E. I

The outer end of one of the chambers or com artments, as a, is closed by the head 7 whi e the outer end of the second compartment or chamber, as b, is open. Threaded upon the outer end of the electrode E is a nut 8 which coacts with the adjacent end of the core G to maintain the electrode in applied position, the opposite end portion of said electrode being provided with an enlargement 9 coacting with the adjacent or firing end of the core C. The outer end portion of the bore of the nut 8 is enlarged to afford a chamber 10 and disposed through the wall of said chamber are the ports 11, preferably three in number, and which provide means whereby air may have ready ingress within the chamber 10.

The portion of the electrode E within the chamber 10 is rovided in its wall with tween the chamber 10 and the chamber or v I compartment a. Also threaded upon the outer end of the electrode E is a second nut 14, the inner endportion of said nut 14 being enlarged, as at 15, whereby said nut 14, when applied, closes the outer or open face of the chamber 10 of the nut 8. The outer portion of the bore of the nut 14 is reduced to provide an eduction vent or port 16, said port or vent 16 being in communication with the upper open end of the compartment or chamber b of the electrode E.

As the eduction port or vent 16 is a material distance above the port 12, an effective up and down draft is eifected through the electrode E, the heated air passing upwardly of the chamber 12 and out through the eduction vent or port ldwhile the cool air is drawn through the ports 11 into the chamber 10 and from the chamber 10 through the port 12 into and downwardly of the chamber or compartment a.

The nuts 8 and 14 may serve as binding elements to hold a suitable conductor in electrical connection with the electrode E and particularly when said conductor is provided with a fiat terminal as now often used. In

the event such conductor is provided with a cates, the wall of the chamber being reeaeee partition dividing the bore into two com- I partments, the outer end of one of the com- 1 partments being closed and the adjacent end of the second compartment being open, the wall of the first compartment being provided with a port in communication with the atmosphere.

2. A spark plug including a hollow electrode having its firing end closed, a partition extending within the bore of the, electrode 7 and terminating at a point spaced from the closed end of the electrode, said partition dividing the bore into two compartments, the outer end of one of the compartments being closed, the wall of said last named compartment being provided with an iduc tion opening, and a member surrounding the electrode and provided with a chamber with which the port of the electrode communiprovided witha port in communication with the atmos here.

3. spark plug including a hollow elec-- trode having its firing end closed, a partition extending within the bore of the electrode and terminating at a point spaced from the closed end of the electrode, said partition dividing the bore into two compartments, the outer end of one of the compartments being closed, the wall of said last named compartment bein provided with an induction opening, a mem er surrounding the electrode and provided with a chamber with which the port of the electrode communicates, the wall of the chamber being pro vided with a port in communication with the atmosphere, a face of the chamber of the member being open, and a nut engaged with the electrode and closing the open face of the chamber of the member, the second chamber of the electrode being in communication with the boreof the nut. a

' 4. A spark plug including a hollow electrode having its nring end closed, a partition extending within the bore of the electrode and terminating at a point spaced from the closed end of the electrode, said partition dividing the bore into two compartments,v the outer end of one of the com: artments being closed, the wall of said ast named compart being provided with an induction openlng, a member surrounding the electrode and provided with a chamber with which the port of the electrode com municates, the wall of the chamber being cation with the bore of the nut, said bore of provided with a port in communication with the nut communicating with the atmosphere the atmosphere, at face of the chamber of the at a point outwardly of the adjacent end of 10 member being open, and a nut engaged with the electrode.

5 the electrode and closing the open face of In testimony whereof I hereunto aflix my the chamber of the member, the second signature.

chamber of the electrode being 1n communi- FRED A. HOMEWOOD. 

